GTK+ 3 Reference Manual: Parsing of custom resources

## Parsing of custom resources

As a consequence of the RC format going away, calling `gtk_rc_parse()` or `gtk_rc_parse_string()` won't have any effect on a widgets appearance. The way to replace these calls is using a custom GtkStyleProvider, either for an individual widget through `gtk_style_context_add_provider()` or for all widgets on a screen through `gtk_style_context_add_provider_for_screen()`. Typically, the provider will be a GtkCssProvider, which parse CSS information from a file or from a string.

Example 17. Using a custom GtkStyleProvider

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    GtkStyleContext *context;
    GtkCssProvider *provider;

    context = gtk_widget_get_style_context (widget);
    provider = gtk_css_provider_new ();
    gtk_css_provider_load_from_data (GTK_CSS_PROVIDER (provider),
                                     ".frame1 {\n"
                                     "   border-image: url('gradient1.png') 10 10 10 10 stretch;\n"
                                     "}\n", -1, NULL);
    gtk_style_context_add_provider (context,
                                    GTK_STYLE_PROVIDER (provider),
                                    GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
    g_object_unref (provider);

Notice that you can also get style information from custom resources by implementing the GtkStyleProvider interface yourself. This is an advanced feature that should be rarely used.